1. Field of the Invention
The present invention relates to a transmission for vehicles. More specifically, it relates to a transmission for vehicles which includes a vibration control mechanism for the gears.
2. Description of Relevant Art
Transmissions for vehicles generally include a number of gear trains in which, at certain point of time, only one gear train is transmitting power, while the other gear trains are not. These idling gear trains have gears which are caused to vibrate by torque variations of the engine. When such vibration occurs, the mutually engaging gears hit each other because of the backlashes, provided therebetween, thus producing noise. The level of this noise rises as the virtual inertia moment of the vibrating gear becomes large. In certain cases, it may rise so high as to give a passenger an unpleasant feeling.
The hitting of gears may be prevented to some extent by possibly reducing respective backlashes of the gears. Where the backlashes are reduced, however, another problem can be caused in that a humming may be produced. Moreover, in the case of automatic and semi-automatic type transmissions in which the speed shifting operation is generally effected by way of an engagement or disengagement of a clutch or a brake under hydraulic pressure, a shock will be caused when shifting the speed.
As a countermeasure to soften the shock in the shifting of speed, there has been proposed a transmission for vehicles in which the transient characteristic is improved for the pressure variation during operation of a clutch or a brake, thereby to make the shifting of speed as smooth as possible. By such way, however, there has not been resulted any sufficient effect in reducing the above-noted vibration problem.
The present invention is accomplished to effectively solve such problems in conventional transmissions for vehicles.